DERIVES DE PYRAZOLOPYRIDINE, COMPOSES THERAPEUTIQUES LES CONTENANT ET PROCEDE DE PREPARATION

PYRAZOLOPYRIDINE DERIVATIVES, THERAPEUTIC COMPOSITIONS COMPRISING SAME, AND PROCESS THEREOF

Abrégé anglais

S P E C I F I C A T I O N
Title of the Invention:
PYRAZOLOPYRIDINE DERIVATIVES, THERAPEUTIC
COMPOSITIONS COMPRISING SAME, AND PROCESS
THEREOF
Abstract of the Disclosure:
New and useful pyrazolopyridine and tetrahydro
pyrazolopyridine derivatives which possess inhibitory
activities on platelet aggregation, and methods for their
production as well as therapeutic compositions containing
these compounds as used in cerebral and peripheral vascular
insufficiency and its complications.

Revendications

The embodiments of the invention in which an exclu-
sive property or privilege is claimed are defined as
follows:
1. A process for the preparation of a compound
having the formula:
<IMG> [I]
in which R is a lower alkyl or alkoxy group, and A is
a) a 3-pyridyl group, or
b) a 4,5,6,7-tetrahydro-3-pyridyl group
which may be substituted at the N-position by:
i) a lower alkyl being unsubstituted or
substituted optionally by a hydroxy or lower alkoxy
group, or
ii) R1-NHCO- wherein R1 is a hydrogen, lower
alkyl or phenyl group which may be substituted by
halogen,
and the pharmaceutically acceptable salts
thereof, wherein:
a) for the preparation of a compound having
the formula:
<IMG>
[IV]
in which R is defined as above, corresponding to a
compound of the formula [I] in which A is a 3-pyridyl
group, said process comprises reacting a compound
having the formula:
19

<IMG>
[II]
wherein R is lower alkyl or alkoxy group, with a
compound having the formula:
<IMG> [III]
wherein X is a reactive leaving group, or a salt
thereof;
b) for the preparation of a compound having
the formula
<IMG> [VI]
in which R is defined as above, corresponding to a
compound of the formula [I] in which A is a tetra-
hydro-3-pyridyl group, said process comprises
hydrogenating a compound having the formula:
<IMG> [V]
wherein R is lower alkyl or lower alkoxy group;
c) for the preparation of a compound having
the formula:
<IMG> [VIII]

wherein R is as defined above, R2 is a lower alkyl
which may be substituted by a hydroxy or lower alkoxy
group, or a phenyl group which may be substituted by
halogen, and n is equal to 0 or 1, corresponding to a
compound of the formula [I] in which A is tetra-
hydro-3-pyridyl which is substituted at the N-
position by a lower alkyl being unsubstituted or
substituted by a hydroxy or lower alkoxy group or by
R1-NHCO- wherein R1 is as defined above, said process
comprises reacting a compound having the formula:
<IMG> [VI]
wherein R is lower alkyl or lower alkoxy group, with
a compound having the formula:
X1 - R2 [VII]
wherein X1 is a nucleophilically exchangeable group,
and R2 is a lower alkyl which may be substituted by a
hydroxy or lower alkoxy group, or a phenyl group
which may be substituted by halogen; and
d) where a pharmaceutically acceptable salt
of the compound obtained is desired, the compound
thus obtained is converted into the desired salt.
2. A process according to claim 1, for the
preparation of a compound having the formula:
<IMG> [IV]
21

in which R has the aforesaid meaning, corresponding
to a compound of the formula [I] in which A is a
3-pyridyl group, said process comprising reacting a
compound having the formula:
<IMG>
[II]
wherein R is lower alkyl or alkoxy group, with a
compound having the formula:
<IMG> [III]
wherein X is a reactive leaving group, or a salt
thereof.
3. A process according to claim 1, for the
preparation of a compound having the formula:
<IMG> [VI]
in which R has the aforesaid meaning, corresponding
to a compound of the formula [I] in which A is a
tetrahydro-3-pyridyl group, said process comprising
hydrogenating a compound having the formula:
<IMG> [V]
22

wherein R is lower alkyl or lower alkoxy group.
4. A process according to claim 1, for the
preparation of a compound having the formula:
<IMG> [VIII]
wherein R has the aforesaid meaning, R2 is a lower
alkyl which may be substituted by a hydroxy or lower
alkoxy group, or a phenyl group which may be substi-
tuted by halogen, and n is equal to 0 or 1, corres-
ponding to a compound of the formula [I] in which A
is tetrahydro-3-pyridyl which is substituted at the
N-position by a lower alkyl being unsubstituted or
substituted by a hydroxy or lower alkoxy group or by
R1-NHCO- wherein R1 has the aforesaid meaning, said
process comprising reacting a compound having the
formula:
<IMG> [VI]
wherein R is lower alkyl or lower alkoxy group, with
a compound having the formula:
X1 - R2 [VII]
wherein X1 is a nucleophilically exchangeable group,
and R2 is a lower alkyl which may be substituted by a
hydroxy or lower alkoxy group, or a phenyl group
which may be substituted by halogen.
23

5. The compounds having the general formula:
<IMG> [I]
wherein R is a lower alkyl or alkoxy group, and A is
a) a 3-pyridyl group, or
b) a 4,5,6,7-tetrahydro-3-pyridinyl group
which may be substituted at the N-position by:
i) a lower alkyl being unsubstituted or
substituted optionally by a hydroxy or lower alkoxy
group,
ii) R1-NHCO- wherein R1 is a hydrogen, lower
alkyl or phenyl group which may be substituted by
halogen,
and the pharmaceutically acceptable salts
thereof.
6. A pharmaceutical composition for treating
cerebral and peripheral vascular insufficiencies,
comprising as active ingredient a compound of the
formula [I] as defined in claim 1, or a pharmaceutic-
ally acceptable salt thereof, together with a pharma-
ceutically acceptable carrier therefor.
24

Description

575i
Background of the Invention:
Field of the Invention:
The present invention relates to certain novel
pyrazolo[l,S-a]pyridine and 4,5,6,7-tetrahydropyrazolo-
[1,5-a]pyridine derivatives, which have inhibitory
activities on platelet aggregation and are useful for
treating cerebral and peripheral vascular insufficiencies
and accompanying complications containing them.
Recently, it is generally accepted that platelets
and/or products of arachidonic acid metabolism have an
important role in the etiology of thrombotic diseases and
arteriosclerosis. Therefore, developments of much more
effective antiaggregants have been greatly desired.
Summary of the Invention:
As a result of extensive investigations, the
present investigators have now unexpectedly found that new
derivatives of pyrazolo[l,5-a]pyridine and 4,5,6,7-
tetrahydropyrazololl,S-a]pyridine having a general formula
[I~ possess a potent inhibitory activity on platelet
aggregation. This is new and unobvious from the known
arts of the similar series.
N ~ -CO~A
[I]
- 2 -

~65~5
[Wherein, R is a lower alkyl or alkoxy group. A is
tetrahydro-3-pyridyl which may be substituted at the
N-position by a lower alkyl being unsubstituted or substi
tuted optionally by a hydroxy or lower alkoxy group, or
Rl-~H~O- (wherein R} is a hydrogen, lower alkyl or phenyl
group which may be substituted by halogen~, or 3-pyridyl
group~.
Thus the present compounds are useful as agents
for preventing or treating, for example, cerebrovascular
disease, thrombosis, migrainia, local anemic infarction,
myocardial ischemia and infarction, vascular complications
accompanied with cancer or diabetes, an~ so on.
This invention also covers the pharmaeeutically
acceptable salts of the compound having the formula [I].
The pharmaeeutieally aeceptable salts mean inorganic salts
such as hydroehloride, hydrobromide, sulfate, phosphate,
and so on, or organie salts sueh as aeetate, maleate,
fumalate, gluconate, suecinate, methansulfonate, or p-
toluene sulfonate, and so on.
The compounds or their salts are used in human
and veterinary medicine in intaet or in pharmaeeutieal
compositions, which additionally comprise an inert
physiologieally aeceptable earrier. For oral or parenteral
administration, suitable forms of pharmaeeutieal composition
are, foL example, compressed tablets, capsules, liquors,
injections, suppositories, powders, syrups and so on.

` ~2~i75
Brief Description of the Drawing:
Fig. 1 shows effects of the compound of Example 2
on the arachidonic acid-induced aggregation of platelets
from rabbit which had been administered orally.
Detailed Description of the Invention:
The compounds of the invention can be prepared by
various methods as follows:
1. Pyrazolo[1,5-a]pyridine and 4,5,6,7-tetrahydro-
[1,5-a]pyridine derivatives [IV~ having the general formula
[I) in which A is 3-pyridyl, can be obtained by the reaction
with a compound indicated by the formula [II] with a compound
indicated by the formula [III] or the salt thereof,
~ + X - CO ~ ~ ~CO~
lII] [III] [IV~
[wherein R is defined as above defined and X means a
reactive leaving group] in an appropriate solvent or in
the absence of a solvent, at a temperature in the range of
room temperature to near 200C. In some cases, the addition
of catalysts, such as, aluminum chloride, sulfuric acid,
phosphoric acid, and so on, may be preferable. Typically,
the compound can be obtained by heating a compound indicated
by the formula [TII] (in which X is a chlorine and which can
be obtained by the reaction of the corresponding carboxylic

- -- i2~S75
acid and chlorinating agent, such as, thionyl chloride) with
a compound indicated by the formula [II] in an appropriate
solvent, such as, nitrobenzene, 1,4-dioxane, and 50 on, at
a temperature in the range of 100 to 200C, preferably
between about 140C and lS0C.
2. Pyrazolo[1,5-a]pyridine and 4,5,6,7-tetrahydro-
pyrazolo[l,5-a~pyridine derivatives[VI-b] having the general
formula [I] in which A is a tetrahydro-3-pyridyl group, can
be obtained by the hydrogenation of a compound indicated by
the formula [V] in an appropriate solvent such as alcohol, at
a hydrogen pressure, for example, in the range of 10 - S0 kg/cm2
in the presence of appropriate catalyst such as palladium
carbon. At a lower temperature (room temperature to about
60C), a compound indicated by the formula [VI-a] can he
obtained, and at a higher temperature (above about 60C), a
compound indicated by the formula [VI-b] can be obtained.
[VI-a~
CO ~ R
~ ~ [VI-b]
1 v ~
[wherein R is defined as hereinabove].
-- 5 --

:~2~i5~5
\
3. Pyrazo~o[1,5-a]pyridine and 4,5,6,7-tetrahydro-
[l,S-a]pyridine derivatives [VIII] having the general
formula [I], [wherein A is a tetrahydro-3-pyridyl group
which is substituted at the N-position by a lower alkyl
(including or not including a substituent, such as, hydroxy
or lower alkoxy group), or Rl-NHCO- ], can be obtained by
the reaction of a compound oE general formula [VI] with a
compound of general formula [VII] in a conventionally
known way. Typically, the compound [VI] is dissolved in
an appropriate solvent, such as dimethylformamide, followed
by addition of sodium hydride, and the resulting anion is
made to react with an alkylating reagent of the general
formula [VII] to afford an N-alkylated compound. In
addition, a compound of the general formula [VII] in which
Xl is an isocyanate, reacts easily with a compound of the
general formula [VI] by mixing them in methylene dichloride.
i i ~ + X~- R -~ ~ C
[VI] [VII] [VIII]
[Wherein Xl is a nucleously convertible group, such as halogen
or sulfonic acid ester, or isocyanate yroup, R2 is a lower
alkyl which may be subs-tituted by a hydroxy or lower alkoxy
group, or a phenyl group which may occasionally be substituted
by halogen, and n is O or :L].
~ ~ - 6 -

575
The pharmaceutically acceptable salts of the
compound of the present invention can be obtained by the
reaction of a free base of the compound of the invention
with a desired acid in an appropriate solvent, in the
usual way.
The following examples illustrate this invention
in detail, however, without restricting it thereto.
Example 1:
Preparation of 2-methyl-3-nicotinoyl-
pyrazolo[l,5-a]pyridine
To a mixture of 107 g of nicotinic acid and 315 ml
of nitrobenzene were added dropwise whilst stirring 107 g of
thionyl chloride, the mixture was warmed for one hour at a
temperature of 160 - 1~0C. The reaction mixture was allowed
to cool, then 35 g of 2-methylpyrazolo[1,5-a]pyridine was
introduced in one portion, and the mixture was heated to
140 - 160C for 2 hours, and poured into 1 Q of ice water.
Next, 50 ml of concentrated hydrochloric acid were added.
This solution was extracted twice with 500 ml of benzene.
After neutralizing with potassium carbonate, the aqueous
layer was extracted with chloroform, the extract was dried
with anhydrous Na2SO~ and after removal of the chloroform,
the residue was chromatographed over SlO2 employing CH2C12-
AcOEt (3 : 2) mixture as eluent. The eluate was evaporated
to dryness in vacuo and the residue was recrystallized
~EtOH - Hexane); yield 30 g (46~), mp 89 - 90C.
-- 7 --

-` ~;Z~6575 ~ N
Anal.Cald. for C14HIoN3O 70.87 4.67 17.71
Found 70.71 4.58 17.47
Example 2:
Preparation of 2-methyl-3-(1,4,5,6-tetrahydro-
nicotinoyl)pyrazolo[l,5-a~pyridine
Ten g of 2-methyl-3-nicotinoyl pyrazololl,5-a]pyridine
was dissolved in 150 ml of absolute ethanol and Z g of 10 %
palladium carbon was added to the solution. The mixture was
hydrogenated in an autoclave at 13 atm. of hydrogen at a
temperature in the range of 55 to 58~C for 3 hours. The
mixture was filtered and the filtrate was evaporated undex
reduced pressure in order to remove the solvent. The residue
was recrystallized from ethyl acetate to afford the title
compound in yield of 8.5 g, mp 207 - 208C.
C H N
Anal.Cald. for Cl4HlsN3O 69.69 6.27 17.42
Found 69.78 6.27 17.31
Example 3:
Preparation of 2-methyl-3-(1,4,5,6-tetrahydro-
nicotinoyl)~4,5,6,7-tetrahydropyrazolell,5-a~-
pyridine
By following the procedure of Example 2, it was
hydrogenated at lS atm. and at 80C, and recrystalli~ed from
ethyl acetate to afford the title compound in yield of 30 g
(74 %), mp 135 136C.
. - 8 -

.~ 124~7S N
Anal.Cald. for Cl4HIgN3O 68.54 7.81 17.13
Found 68.35 7.81 16.98
Example 4:
Preparation of 2-methyl-3-[1-(p-chlorophenyl-
carbamoyl)-1,4,5,6-tetrahydronicotinoyl]-
pyrazolo[l,5-a]pyridine
One g of 2-methyl-3-(1,4,5,6-tetrahydronicotinoyl)-
pyrazolo[l,5-a]pyridine was dissolved in 20 ml of methylene
chloride and 1 g of p-chlorophenyl isocyanate was added
dropwise whilst stirring to the solution. The mixture was
stirred at room temperature for 2 hours, and after removal
of solvent in vacuo, the residue was recrystallized from
ethyl acetate to afford the title compound in yield oE 1.2 g
(73 ~), mp. 198 - 200C.
C H N
Anal.Cald. for C2lHIgN4O2Cl 63.88 4.85 14.19
Found 63.89 4.8414.19
Example 5:
Preparation of 2-methyl-3-(1-ethyl-1,4,5,6~
tetrahydronicotinoyl)pyrazolo[l,5-a~pyridine
One g of 2-methyl-3-(1,4,5,6-tetrahydronicotinoyl)-
pyrazolo[l,5-a)pyridine was dissolved in 20 ml of dimethyl-
formamide and 0.3 g of sodium hydride (55 %) was added whilst
stirring to the mixture. The mixture was stirred at room
temperature for 1 hour, and then 1 g of ethylchloride was
added and stirred at 60C for 2 hours. After removal of

~2~57~i
solvent in vacuo, the residue was chromatographed over sio2
employing CH2Cl 2 - ethyl acetate - methanol t 8 : 1.5 : 0.5)
mixture as eluent. The eluate was evaporated to dryness in
vacuo and the residue was recrystallized from benzene-hexane
to afford the title compound in yield of 0.8 g (72 %),
mp. 104 - 105C.
C H N
Anal.Cald. for C~6HI9N30 71.34 7.11 15.60
Found 71.05 7.09 15.42
xample 6:
Preparation of 2-isopropyl-3-(1,4,5,6-tetra-
hydronicotinoyl)pyrazololl,5-a]pyridine
It was prepared following the procedure of Example
2, and recrystallized from ethyl acetate to afford the title
compound in yield of 66 ~, mp. 186 - 188C.
C H N
Anal.Cald. for C~6H~gN30 71.34 7.11 15.72
Found 71.33 7.14 15.55
Example 7:
Preparation of 2-isopropyl-3-nicotinoyl-4,5,
6,7-tetrahydropyrazolo~1,5-a]pyridine
It was prepared followin~ the procedure of
Example 1, and obtained as oily product in yield 41 3,
ass, m/e 269 ~M ).
-- 10 --

` ~ 575
Example 8:
Preparation of 2-isopropyl-8-(1,4,5,6-tetra-
hydronicotinoyl)-4,5,6,7-tetrahydropyrazolo-
[1,5-a]pyridine
It was prepared follo~ing the procedure of
Exam~le 3, and recrystallized from benzene-hexane to
afford the title compound in yield of 11 %, mp. 123 - 125C.
C H N
Anal.Cald. for C,6H23N3O 70.29 8.48 15.37
Found 70.03 8.44 15.21
~xample 9:
Preparation of 2-methyl-3-nicotinoyl-
pyrazololl,5-a~pyridine
To a solution of 110 g of 2-methylpyrazolo~1,5-a~-
pyridine in 600 ml of 1,4-dioxane was added 150 g of nicotinyl
chloride hydrochloride with stirring. The resulting solution
was heated to reflux for 2 hours, and after removal of solvent
in vacuo, the residue was dissolved in 500 ml of water and
neutralized with potassium carbonate. The aqueous layer was
extracted with 500 ml of benæene, the extract was dried over
anhydrous Na2So4, and after removal of solvent, the residue
was recrystallized from ethyl acetate-hexane to afford 110 g
of the title compound. Concentrating the mother liquors gave
a second crop of crystals, which weighed 10 g; total yield
120 g (61 %), mp. 89 - 90C.
C H N
Anal.Calcd. for C~4HloN30 70.87 4.67 17.71
Found 70.91 4.67 17.68
- 11-

575
Example 10:
Preparation of 3-[1~ ethoxycarbonylethylj-
1~4~5~6-tetrahydronicotinoyl]-2-methylpyrazolo-
~1,5-a]pyridine
It was prepared following the procedure of Example 5,
and recrystallized from ethyl acetate-hexane to afford the
title com~ound in yield of 60 %, mp. 107 ~ 108C.
C H N
Anal.Cald for ClgH23N3O3 66.84 6.79 12.31
Found 66.76 6.89 12.19
The experiments to prove usefulness of the compounds
of this invention are detailed as follows.
Experiment 1:
In vitro studies on platelet aggregation
The antiaggregant activity in vitro of the present
compounds was studied in platelet rich plasma from rabbit
and man.
(A) Effects on rabbit platelet aggregation
Blood was taken from the femoral artery of rabbit
with a syringe containing sodium citrate (3.8 ~, 1 vol. in
9 vol. of blood). The citrated blood was centrifuged at
800 rpm. The supernatants were stored at 10C until use
as platelet rich plasma (PRP) in the subsequent experiment.
Platelet aggregation was determined with aggregometer
(~-P 247 E, SIENCO Ltd.). Stock solution of test compounds
was made by suspending at a concentration of 10 mg/ml in
~1 ~ gum arabic solution. Further, dilution was made with
- 12 -

24~57~;
0.9 % saline. PRP was preincubated for 3 min. with the
test compounds, and then arachidonic acid as aggregant was
added a~ final concentration of 10 ~.
The antiaggregant activities of the compounds are
shown in Table 1. IC~00-values are the concentrations which gave
maximum (100 %) inhibition against platelet aggregation
caused by arachidonic acid.
(B) Effects on human platelet aggregation
Blood samples were taken from median cubital vein
of 5 healthy volunteers (male, 30 to 42 age ) with plastic
syringe. The citrated blood (sodium citrate 1 vol. in 9 vol.
of blood) was centrifuged at 1000 rpm. The supernatant (PRP)
was stored at 10C and used within 5 hours. Arachidonic acid
(4 - 8 x 10-4M) and collagen (6 - 8 ~g/ml, SIG~lA, Type III)
were used as aggregants. Other procedures were the same as
in Experiment 1.
The results of this experiment show that the compound
of Example 2 has potency and almost the same inhibitory
activity against both arachidonic acid- and collagen-induced
platelet aggregation. IC~00-values of this compound are in the
range of 10-1to 3 x 10~Bg/ml. About 300-folds difference in
the IC~00-values is considered to be due to individual difference.
On the other hand, a reference drug, aspirin, completely
inhibited both arachidonic acid- and collagen-induced platelet
aggregation only at concentration as high as 6 - 8 x 10- 6 g/ml
and 10- 4 g/ml, respectively.
- 13 -

S75
Experiment 2:
Ex vivo studies on platelet aggregation
To know the absorbability and potency of the
compound of this invention, another platelet aggregation
tests were done using the PRP from rabbit which had been
administered orally with the drugs.
Rabbits were administered orally with the compound
of Example 2 or aspirin. One hour after the drug administ-
ration, blood was taken from the femoral artery. The
methods for ~reparing PRP and determining platelet aggre-
gation were the same as Experiment 1~ The results given in
Fig. 1 indicate that tl~e compound of Example 2 has potent in-
hibitory activity several times as high as aspirin on arachidonic
acid-induced platelet aggregation.
Experiment 3:
Effect on blood viscosity
Male Wistar rats weighing 300 - 380 g were used in
this experiment. Rats were administered orally 10 mg/kg
twice a day of the compound of Example 2 for 2 days. One
hour after the last treatment, rats were anaesthetized with
pentobarbital 35 mg/kg ip, and then blood was taken from vena
cava caudalis. EDT.~ was added at a final concentration of 2 ~.
l~hole blood and plasma viscosities were measured with
rotational viscometer (Contraves ~S-30, shear rate 0 - 12~.5
sec. , 37C) and hematocrit was determined by microhematocrit
centrifugation (13,000 g for S min.).
- 14 -

~2~57~
, ~
As shown in ~able 2, whole blood viscosities at
shear rate 0.1285, 0.514, 6.425, 25.7 and 128.5 sec. ~ were
reduced by 50.1, 36.1, 23.5, 19.2 and 12.0 ~, respectively,
but no effects on plasma viscosity and hematocrit were
observed.
Experiment 4:
Gastro-intestinal lesions in rats
Male Wistar rats weighing 250 to 300 g were used in
this experiment. Ulcer formation under the satiety condition
was studied as follows : Rats not fasted prior to experiment
were administered orally with test compounds. The animals
were allowed free access to diet and water for 24 hours after
the drug administration until sacrificed by exsanguination.
The stomach and the intestine were removed and examined for
lesions .
In the other study, rats had been deprived of food
and water for 24 hours before drug administration. The animals
were administered orally with the compound of Example 2 and
aspirin and then they had free access to water but not to diet.
Twenty-four hours later, the animals were killed by the
exsanguination. The stomach and the intestine were removed
and observed carefully to know whether or not lesions were
present.
As shown in Table 3, the ulcerogenic activity of
the compound is 1/4 to 1/10 of that of aspirin.

~Z~575
, . . .
Experiment 5:
Acute Toxicity ~LDso)
Acute toxicity of the compound of Example 2
on Wistar rats and ICR mice are shown in Table 4.
Table 1
Effects of the Compounds on Rabbit Platelet
Aggregation Induced by Arachidonic Acid
Example No.l IC~OO(g/ml)
1 1 6x10-6
2 1, 3 x 10-~
3 1l 2 x 1o-7
4 lxlO-~
3 x 10-~
Aspl rin 4 x 10
~ 16 -

65 75
Tahle 2
Effects of the Compound of Exam~le 2 on
Blood Viscosities and Hematocrits in Rats
Vehiele ¦ Example 2
Shear Rate(see.-l) Whole Blood Viseosity (mPS)
0.1285 49.7 + 6.47 24.8 ~ 2.71*
0-514 26.9 ~ 2.08 17.2 + 1.31*
6.425 9.55 + 0.56 7.31 + 0.36*
25.7 6.41 + 0.25 5.1$ + 0.12*
128.5 4.18 ~ 0.09 3.68 + 0.08*
_ l '
i Plasma Viscosity (mPS)
_ :
1.15 + 0.01 1.14 + 0.01
Hematoerit (%)
46-1 + 1-15 1 46-0 + 0.71
* : Si~nifieant differenee from vehiele,
p < 0.05 (Wileoxon's rank sum test)

24t6S~S
Table 3
Ulcerogenic Activity of the Compounds
Example 2 Aspirin
'i
Satiety ~ 1000 230
¦Fasting 300 ~ UDso~5oo 25 c UDso ~50
,
Units for the UDsO-values: mg/kg, ~.o.
UDso means the dose that cause the lesions
in 50 % of animalsO
Table 4
Acute Toxicity of Example 2
¦ MICE I RATS
P.O. (mg/kg) >1000 j ~1000
I.V. (mg/kg) 125 < LDso <150 i > 100
- 18 -